Microwave oven is a device for generating microwave from a magnetron by supplying a current to irradiate the microwave to a target object such as the food, thereby heating the food. The microwave oven is classified into a general microwave oven and a combined hood and microwave oven. The general microwave oven is used on kitchen furniture. The combined hood and microwave oven is provided on a wall surface over a gas oven range. Additionally, the microwave oven can have a general door where opening and closing are laterally performed or a drop down door where opening and closing are performed up and down. The microwave oven with the drop down door is described as an example of the present invention.
Alternatively, the microwave oven has a tendency of large-sizing a food housing capacity to more quickly cook a large amount of food. However, as the microwave oven is large-sized for the above-purpose, the microwave oven generates much moisture during the cooking of the food. Accordingly, a method for removing the generated moisture is much required. Further, as the microwave oven has a large capacity, an electronic equipment chamber including the magnetron generates much heat. Accordingly, a method for removing the generated heat is also required.
In detail, hot and humid air exhausted from one side of the microwave oven has a difference from an external air in temperature by a predetermined level. Therefore, vapor contained in the exhausted air is condensed. In particular, there is a drawback in that if a glass forming an exterior of the microwave oven is exposed to the hot and humid air, dew is generated at a surface of the glass. Due to the above drawback, a user feels unpleasantness, and corrosion occurs in case where particles of the food are contained in the condensed air.
Further, electronic equipments of a large-sized microwave oven generate a large amount of heat. If the heat is not dissipated enough, it causes abnormal operations of the electronic equipments. Therefore, a new air passage structure for a microwave oven is required to introduce air enough to cool the electronic equipments and quickly exhaust hot air that was used for cooling the electronic equipments.